Hi, I put this on the FWB forum, but in the (many) hours I've spent on this forum, I've learned that there are a lot of tekkies about that don't mind getting into the oily bits:)

This is in bits on the bench, so am needing quick info if possible. I wrote....

Couple of questions on the mini-pump if anyone know how they work.

I finally got round to working on the air compressor on my 95 FWB. There was no rain shielding, and that was the problem. The 30amp fuse had popped before I got the car, so I put in a 60watt bulb, and strung it to where I was working to check the circuit. Sure enough the bulb lit and the relay buzzed when the IGN was turned on. Blowing the suspension line up with air raised the back and turned off the power to the pump relay. So, it seemed that all was working downstream of the pump to the rear. I was lazy and did this with the wheel on (turned hard right) so could not see if the front should rise as well. Should all four be air powered?

The connectors were like new inside, but the motor and pump were dry and full of corrosion. To my surprise, cleaning the comm and oiling the piston allowed it to run on the bench. The thing is, I have no idea how this little pump should be lubricated. Wet sump? Anyone know?

However, although I felt that I was winning for a time, I tried to clear the filter/NRV/buffer that is attached to the pump. Bits of glass-like stuff came out, and although it does give a non-return function, it does not stop all the air seeping back. Should this be totally closed in one direction, or do the valves in the mini-pump act as a Non Return Valve?